FIRESTONE, Colo. — Two people were declared missing and in the rubble of a two-story home that was leveled in an explosion and fire, the Frederick Firestone Fire Protection District said Tuesday morning.

Two people were injured, including a science teacher at Mountain Range High School in Westminster and a child.

Investigators will go in and remove the rubble to search for the two, a process that will be very slow, fire spokeswoman Summer Campos said.

The explosion and fire happened about 4:45 p.m. Monday in the 6300 block of Twilight Avenue near Colorado and Firestone boulevards.

An unidentified child was taken to a hospital and Martinez’s wife, Erin Martinez, was airlifted by Flight for Life in critical condition. The child’s condition is not known.

Erin Martinez is a science teacher at Mountain Range High School, Adams 12 Five Star Schools said. The Martinezes have two children, a boy and a girl.

The investigation by Frederick Firestone Fire Protection District, the Colorado Bureau of Investigation and the Firestone Police Department into the cause of the explosion could take weeks, Campos said.

The American Red Cross said it is assisting two adults from the house and two adults from a neighboring home who were affected.

A GoFundMe page has been set up to help the Martinez and Irwin families. More than $20,000 was raised in the first four hours of the fundraising campaign.

A vigil will be held at 7:30 p.m. Tuesday at Rocky Mountain Christian Church. Donations for the Martinez children, including clothes, toys, household items and toiletries, are being collected at New Image Salon (322 Fifth St.) in Frederick.